docs: def pass_result(db: JobDB, always_cache=False):
      """Creates a pull stream receiving results, storing them in the database,
      then sending them on. At this stage, the database may return a list of
      attached jobs which also need to be sent on to the scheduler."""
      @pull
      def pass_result_stream(worker_source):
          """Pull stream instance created by `pass_result`."""
          for result in worker_source():
              if result is EndOfQueue:
                  return
  
              attached = db.store_result_in_db(
                  result, always_cache=always_cache)
  
              yield result
              yield from (ResultMessage(key, 'attached', result.value, None)
                          for key in attached)
  
      return pass_result_stream